JP5470750B2 - Amine compound, electrophotographic photoreceptor, image forming apparatus - Google Patents

Description

  The present invention relates to an amine compound, an electrophotographic photoreceptor, and an image forming apparatus.

  In recent years, there are increasing opportunities to use electrophotographic copying machines and printers in the fields of printing and color printing. In the fields of printing and color printing, there is a strong tendency to demand high-quality digital monochrome images or color images. In response to such a demand, it has been proposed to form a high-definition digital image using a short-wavelength laser beam as an exposure light source (see, for example, Patent Document 1).

  However, even if the short-wavelength laser light is used to reduce the dot diameter of the exposure and a fine electrostatic latent image is formed on the electrophotographic photosensitive member, the finally obtained electrophotographic image has sufficient high image quality. The current situation has not been achieved.

  The cause is that the photosensitive characteristics of the electrophotographic photosensitive member and the charging characteristics of the toner of the developer do not have sufficient characteristics necessary for forming a fine dot latent image or forming a toner image.

  That is, as an electrophotographic photoreceptor, an organic photoreceptor developed for a conventional long wavelength laser (hereinafter, simply referred to as a photoreceptor) has poor sensitivity characteristics, and the exposure dot diameter is reduced using a short wavelength laser beam. When the narrowed image exposure is performed, the dot latent image is not clearly formed, and the reproducibility of the dot image tends to deteriorate. This is caused not only by the charge generation layer but also by the charge transport layer. It is necessary to identify and remove the deterioration factors of the materials and additives of each layer with respect to the short wavelength laser.

  As a deterioration factor in the charge transport layer, a charge transport material developed for a conventional organic photoreceptor easily absorbs short wavelength light of 300 to 500 nm, and the charge transport material is deteriorated by the short wavelength light. It is presumed that deterioration of electrophotographic characteristics such as a decrease in sensitivity and an increase in residual potential are likely to be promoted.

In response to such a problem, a polyarylalkane compound having a phenyl group methyl-substituted at the para position as a charge transport material has been proposed (see, for example, Patent Document 2).
JP 2000-250239 A JP 2006-104183 A

  However, a charge transport material that does not deteriorate even when irradiated with short-wavelength light has not yet been developed.

  The present invention provides a print image having excellent sharpness without image defects (for example, occurrence of spot defects or fogging in a halftone portion) even when a large number of sheets are printed using an image forming apparatus equipped with a short wavelength laser beam. An object is to provide an amino compound, an electrophotographic photosensitive member, and an image forming apparatus as charge transport materials that can be formed.

  The present invention is achieved by adopting the following configuration.

1. An amine compound characterized by being one of the following compounds CTM-1, CTM-2, CTM-3, CTM-6 and CTM-13 .

2 . An electrophotographic photoreceptor comprising a photosensitive layer containing a charge generation material and a charge transport material on a conductive support, wherein the charge transport material is an amine compound represented by the following general formula (1): An electrophotographic photoreceptor .

(In the general formula (1), Ar ¹ , Ar ² , Ar ⁴ and Ar ⁵ each independently represent a phenyl group which may have one or two methyl groups, and Ar ³ and Ar ⁶ each represent (Independently represents a phenylene group which may have one methyl group. X ¹ and X ² represent the structure represented by the general formula (2).)
(In general formula (2), R _{1 to} R ₈ are each independently hydrogen or a methyl group, and R ₉ represents a biphenyl group or a biphenyloxy group. )

3 . 3. The electrophotographic photosensitive member according to 2 above, wherein the charge generating material contained in the photosensitive layer is a polycyclic quinone compound.

4 . An image having exposure means for forming an electrostatic latent image on a photosensitive member using a semiconductor laser having an oscillation wavelength of 350 to 500 nm or a writing light source of a light emitting diode, and developing means for developing the electrostatic latent image into a toner image 4. An image forming apparatus according to claim 2, wherein the photoconductor is the electrophotographic photoconductor described in 2 or 3 above .

  The amine compound of the present invention does not deteriorate even when exposed to a short wavelength laser beam. When the amino compound is used as a charge transport material for an electrophotographic photoreceptor, a large number of image forming apparatuses equipped with a short wavelength laser beam are used. Even when the sheets are printed, there is no image defect (for example, occurrence of a dot defect or fogging in the halftone portion), and an excellent effect of forming a print image having excellent sharpness can be obtained.

  The inventors of the present invention have examined the cause of potential characteristic deterioration when a large number of sheets are printed using an image forming apparatus equipped with a short wavelength laser beam.

  As a result of various studies, it was found that the charge transport material was degraded (decomposed) by the short wavelength light. Therefore, a search was made for a charge transport material that does not deteriorate (decompose) even when irradiated with short-wavelength light.

  The inventors of the present invention considered that it is possible to prevent deterioration (decomposition) of the charge transport material itself by converting energy generated when irradiated with a wavelength of 300 to 400 nm into fluorescence.

  As a result of various studies, an amino compound having a substituent that can absorb fluorescence at a wavelength of 300 to 400 nm, such as a biphenyl group or a naphthyl group, has no absorption at a wavelength exceeding 400 nm, and can emit fluorescence is used as a charge transport material. The photoconductor has improved light resistance to short wavelength light, and even if a large number of sheets are printed using an image forming apparatus equipped with a short wavelength laser beam, an image defect (for example, a dot defect in a halftone portion or fogging) It has been found that a print image having excellent sharpness can be formed.

  Specifically, a charge transport material into which a substitution machine having a specific structure was introduced was examined.

  As a result of various studies, it has been found that when a triarylamine compound having a specific structure is used as a charge transport material, deterioration can be prevented even when irradiated with short-wavelength light. Photoreceptors produced using this compound have improved light resistance to short-wavelength light, and image defects (for example, occurrence of spot defects and fogging in halftone areas) and sharpness are reduced even when a large number of sheets are printed. The problem of the present invention could be solved.

  Hereinafter, the present invention will be described in detail.

  The amine compound of the present invention is represented by the following general formula (1).

(In general formula (1), Ar ¹ , Ar ² , Ar ⁴ , Ar ⁵ each independently represents an aryl group which may have a substituent, and Ar ³ , Ar ⁶ each independently represents a substituent. X ¹ and X ² each independently represents an alkyl group, an aryl group or an alkoxyl group which may have a substituent, and is linked to form a cyclic structure containing a heterocyclic ring (In addition, Ar ^{1 to} Ar ⁶ and any one of X ¹ and X ² include one or more substituents composed of a biphenyl group, a naphthyl group, or a derivative thereof.)
In the structure of the general formula (1), X ¹ and X ² are preferably structures represented by the general formula (2).

(In General Formula (2), R _{1 to} R ₈ are each independently hydrogen or an alkyl group having 1 to 4 carbon atoms, and R ₉ is a substituent composed of a biphenyl group, a naphthyl group, or a derivative thereof. Including one or more)
The amine compound represented by the general formula (1) emits fluorescence with respect to a short wavelength of 380 to 500 used as a laser light source, has a large potential decay value with respect to unit exposure, has good repeatability, and has a small diameter. Charge transport layer after coating when the latent image can be formed sharply, improved in solvent solubility, compatibility with polycarbonate and other binders, and used as a charge transport material for electrophotographic photoreceptors The film has excellent properties that improve the physical properties of the film.

  As a result, the electrophotographic photosensitive member produced using the amine compound of the general formula (1) as a charge transporting substance has no image defect and is sharp even when an image is formed using a light source having a short wavelength of 380 to 500 nm. An excellent print image can be obtained.

  First, the amino compound of the present invention will be described.

  The amino compound of the present invention is a compound represented by the general formula (1), such as CTM-1 shown in the exemplified compound in which a biphenyl group or a naphthyl group is introduced into the central part of the compound.

  Although the specific example of the amine compound of the said General formula (1) is illustrated below, the amine compound of this invention is not limited to these specific examples.

  Below, the synthesis example of the amine compound represented by General formula (1) is illustrated.

(Synthesis Example 1): Synthesis of Compound CTM-1 In a four-necked flask, 11 parts by mass of N, N-bis (p-methylphenyl) aniline, 6 parts by mass of 4- (4-biphenyl) cyclohexane, and acetic acid were added. 100 parts by mass was measured, and 4.1 parts by mass of hydrochloric acid was further added. After stirring for 14 hours at 75 to 85 ° C. in a nitrogen stream, the mixture was cooled to room temperature, 150 parts by mass of toluene and 100 parts by mass of water were added, and the mixture was washed with a separatory funnel until the aqueous layer became neutral. The toluene layer was transferred to an eggplant flask and concentrated. After concentration, the target product was separated and purified by column chromatography. The yield was 14.9 parts by mass. The structure of the obtained compound was confirmed by nuclear magnetic resonance spectrum and mass spectrum.

(Synthesis Example 2): Synthesis of Compound CTM-2 The raw material N, N-bis (p-methylphenyl) aniline used in the synthesis of CTM-1 was replaced with 3,4-dimethyl-N-phenyl-Np-tolylineline. CTM-2 was synthesized in the same manner except that it was changed to. The structure of the obtained compound was confirmed by nuclear magnetic resonance spectrum and mass spectrum.

(Synthesis Example 3): Synthesis of Compound CTM-3 The same as that except that 4- (4-biphenylyl) cyclohexonee used in the synthesis of CTM-1 was changed to 4- (2′-methylbiphenyl-4-) cyclohexonee Thus, CTM-3 was synthesized.

  The structure of the obtained compound was confirmed by nuclear magnetic resonance spectrum and mass spectrum.

(Synthesis Example 4): Synthesis of Compound CTM-6 The raw material 4- (4-biphenylyl) cyclohexone used in the synthesis of CTM-1 was changed to 4- (biphenyl-4-yl) -3-methylcyclohexone, Similarly, CTM-6 was synthesized.

  The structure of the obtained compound was confirmed by nuclear magnetic resonance spectrum and mass spectrum.

  The structure of the photoreceptor according to the present invention will be described below.

  The structure of the photoreceptor according to the present invention is not particularly limited as long as it contains the amine compound of the general formula (1) as a charge transport material, and examples thereof include the following structures.

(1) Structure in which a charge generation layer and a charge transport layer are laminated as a photosensitive layer on a conductive support (2) An intermediate layer and a charge generation layer and a charge transport layer as a photosensitive layer are sequentially laminated on the conductive support. Configuration (3) Configuration in which a single layer containing a charge transport material and a charge generation material is formed as a photosensitive layer on a conductive support. (4) Further surface on the photosensitive layer of the photosensitive body of (1) to (3) above. A configuration in which a protective layer is formed.

  Note that, regardless of the configuration of the photoreceptor according to the present invention, an undercoat layer (intermediate layer) is provided between the support and the photosensitive layer on the conductive support before the formation of the photosensitive layer. It may be formed.

  The charge transport layer means a layer having a function of transporting charge carriers generated in the charge generation layer by photoexposure to the surface of the organic photoreceptor, and the specific detection of the charge transport function is carried out between the charge generation layer and the charge transport layer. It can be confirmed by laminating a transport layer on a conductive support and detecting optical conductivity.

  Next, the layer structure of the photoconductor will be described focusing on the structure (2).

(Conductive support)
The conductive support used for the photoreceptor may be either a sheet or a cylinder, but a cylindrical conductive support is preferable for designing the image forming apparatus in a compact manner.

  Cylindrical conductive support means a cylindrical support necessary for forming an endless image by rotating. Conductivity is within a range of 0.1 mm or less in straightness and 0.1 mm or less in deflection. These supports are preferred. Exceeding the range of straightness and shake makes it difficult to form a good image.

As a material for the conductive support, a metal drum such as aluminum or nickel, a plastic drum deposited with aluminum, tin oxide, indium oxide, or the like, or a paper / plastic drum coated with a conductive substance can be used. The conductive support preferably has a specific resistance of 10 ³ Ωcm or less at room temperature. The conductive support used in the present invention is most preferably an aluminum support. As the aluminum support, one in which components such as manganese, zinc, magnesium and the like are mixed in addition to the main component aluminum is also used.

(Middle layer)
In the present invention, it is preferable to provide an intermediate layer between the conductive support and the photosensitive layer because the defect of the conductive support can be covered.

  The binder resin for the intermediate layer is preferably an alcohol-soluble polyamide resin. As the binder resin for the intermediate layer of the organic photoreceptor, a resin having excellent solvent solubility is required in order to form the intermediate layer with a uniform film thickness. As such an alcohol-soluble polyamide resin, a copolymerized polyamide resin or a methoxymethylated polyamide resin composed of a chemical structure having few carbon chains between amide bonds such as 6-nylon is used.

  The intermediate layer coating solution used in the present invention is composed of the binder resin and the solvent. Preferably, a solution obtained by dispersing and adding surface-treated N-type semiconductive particles is used.

As the N-type semiconductor particles, titanium oxide (TiO ₂ ) and zinc oxide (ZnO) are preferable, and titanium oxide is particularly preferably used.

  The surface treatment of the N-type semiconductor particles is preferably a surface treatment with a polymer containing methylhydrogensiloxane units.

  The ratio of the N-type semiconductive particles in the intermediate layer is preferably 1.0 to 2.0 times in terms of the volume ratio of the intermediate layer to the binder resin (when the volume of the binder resin is 1). By using such high-density N-type semiconducting particles in the intermediate layer, the rectification of the intermediate layer is increased, effectively preventing an increase in residual potential and dot image degradation even when the film thickness is increased. And a good organic photoreceptor can be formed. Further, such an intermediate layer preferably uses 100 to 200 parts by volume of N-type semiconductive particles with respect to 100 parts by volume of the binder resin.

  On the other hand, the binder resin in which these particles are dispersed to form the layer structure of the intermediate layer is preferably a polyamide resin in order to obtain good dispersibility of the particles, but the polyamide resin shown below is particularly preferable.

  The binder resin for the intermediate layer is preferably an alcohol-soluble polyamide resin. As the binder resin for the intermediate layer of the organic photoreceptor, a resin having excellent solvent solubility is required in order to form the intermediate layer with a uniform film thickness. As such an alcohol-soluble polyamide resin, a copolymerized polyamide resin or a methoxymethylated polyamide resin composed of a chemical structure having few carbon chains between amide bonds such as 6-nylon is used.

(Photosensitive layer)
The layer structure of the photosensitive layer according to the present invention may be a single layer structure in which the charge generation function and the charge transport function are provided on one layer on the intermediate layer, but the function of the photosensitive layer is more preferably charged. It is preferable to take a layer structure in which the generation layer (CGL) and the charge transport layer (CTL) are separated. By taking a layer structure with separated functions, it is possible to control the increase in residual potential with repeated use and to easily control other electrophotographic characteristics according to the purpose. In the negatively charged photoconductor, it is preferable that a charge generation layer (CGL) is formed on the intermediate layer, and a charge transport layer (CTL) is formed thereon.

  Hereinafter, the photosensitive layer of the function-separated negatively charged photoreceptor will be described.

(Charge generation layer)
The charge generation layer according to the present invention is preferably formed using a charge generation material having high sensitivity characteristics in a wavelength region of 380 nm to 500 nm as a charge generation material. As such a charge generating substance, titanyl phthalocyanine compound, gallium phthalocyanine compound, azo compound, perylene compound, polycyclic quinone compound and the like are preferably used.

  In particular, the X-ray diffraction spectrum by Cu-Kα characteristic X-ray having a high sensitivity to a commercially available short wavelength laser having an oscillation wavelength of around 405 mm, and a titanyl phthalocyanine compound having a maximum peak angle of 2θ and 27.3 ° A polycyclic quinone compound of dipromanthanthrone or a polycyclic quinone compound represented by the following general formula (CGM-3a) is preferably used.

  These compounds can be used in combination.

  When a binder resin is used as a CGM dispersion medium during the formation of the charge generation layer, a known resin can be used as the binder. Preferred resins include formal resin, butyral resin, silicone resin, silicone-modified butyral resin, and phenoxy. Examples thereof include resins. The ratio of the binder resin to the charge generating material is preferably 20 to 600 parts by mass with respect to 100 parts by mass of the binder resin. By using these binder resins, the increase in residual potential due to repeated use can be minimized. The thickness of the charge generation layer is preferably from 0.3 to 2 μm.

(Charge transport layer)
The charge transport layer contains a charge transport material (CTM) and a binder resin. Other substances may contain additives such as antioxidants as necessary.

  As the charge transport material (CTM), the amine compound of the general formula (1) is used, but in addition to this, a known hole transport property (P-type) charge transport material (CTM) may be used in combination. . For example, a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, a butadiene compound, or the like can be used. These charge transport materials are usually dissolved in a suitable binder resin to form a layer.

  The binder resin used for forming the charge transport layer (CTL) may be either a thermoplastic resin or a thermosetting resin. For example, polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin, melamine resin, and these resins A copolymer resin containing two or more of the repeating unit structures. In addition to these insulating resins, high molecular organic semiconductors such as poly-N-vinylcarbazole can be used. Among these, a polycarbonate resin having a low water absorption rate and excellent CTM dispersibility and electrophotographic characteristics is preferable.

  The ratio of the binder resin to the charge transport material is preferably 50 to 200 parts by mass with respect to 100 parts by mass of the binder resin.

  The thickness of the charge transport layer is preferably 10 to 25 μm. By setting the thickness of the charge transport layer to 10 μm or more, a latent image potential at the time of development can be sufficiently obtained, and image density reduction and dot reproducibility deterioration do not occur. In addition, when the thickness of the charge transport layer is 25 μm or less, the diffusion of charge carriers (the diffusion of charge carriers generated in the charge generation layer) is small, and the dot reproducibility is good.

  Solvents or dispersion media used to form layers such as intermediate layers, charge generation layers, and charge transport layers include n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, acetone , Methyl ethyl ketone, methyl isopropyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, 1,2-dichloroethane, 1,2-dichloropropane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, trichloroethylene, Tetrachloroethane, tetrahydrofuran, dioxolane, dioxane, methanol, ethanol, butanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cello Lube, and the like. Although it is not limited to these in this invention, Solvents friendly to global environment, such as tetrahydrofuran and methyl ethyl ketone, are used preferably. These solvents may be used alone or as a mixed solvent of two or more.

  As a method for forming the intermediate layer, the charge generation layer, the charge transport layer, and the like, a coating processing method such as dip coating and spray coating is used in addition to the slide hopper type coating device.

  Next, the image forming apparatus according to the present invention will be described.

  The image forming apparatus according to the present invention includes an exposure unit that forms an electrostatic latent image on a photoconductor using a writing light source, and a developing unit that visualizes the electrostatic latent image into a toner image.

  A photoreceptor formed using the amino compound of the present invention as a charge transport layer is used as the photoreceptor, and a spot light source having a wavelength of 380 to 500 nm is used as the exposure means.

  In addition, as a spot light source having a wavelength of 380 to 500 nm, an ultraviolet laser (laser oscillation wavelength 380 nm), a violet laser (laser oscillation wavelength 408 nm), a blue laser (laser oscillation wavelengths 440 nm and 500 nm), a light emitting diode (emission wavelength 450 nm), etc. Can be used.

  The image forming apparatus according to the present invention is generally applicable to electrophotographic apparatuses such as an electrophotographic copying machine, a laser printer, an LED printer, and a liquid crystal shutter printer, but also displays, recordings, light printing, It can be widely applied to apparatuses such as plate making and facsimile.

  The image forming apparatus will be specifically described below.

  FIG. 1 is a cross-sectional configuration diagram illustrating an example of an image forming apparatus in which a photoconductor according to the present invention can be used.

  An image forming apparatus 1 shown in FIG. 1 is a digital image forming apparatus, and includes an image reading unit A, an image processing unit B, an image forming unit C, and a transfer paper transport unit D as a transfer paper transport unit. Yes.

  An automatic document feeder that automatically conveys the document is provided above the image reading unit A, and the document placed on the document placing table 11 is separated and conveyed by the document conveying roller 12 to the reading position 13a. Then, the image is read. The document that has been read is discharged onto the document discharge tray 14 by the document transport roller 12.

  On the other hand, the image of the original when placed on the platen glass 13 is read at a speed v of the first mirror unit 15 comprising the illumination lamp and the first mirror constituting the scanning optical system, and the V-shaped first image is located. Reading is performed by the movement of the second mirror unit 16 including the two mirrors and the third mirror in the same direction at the speed v / 2.

  The read image is formed on the light receiving surface of the image sensor CCD, which is a line sensor, through the projection lens 17. The line-shaped optical image formed on the image sensor CCD is sequentially photoelectrically converted into an electric signal (luminance signal) and then A / D converted, and the image processing unit B performs processing such as density conversion and filter processing. Then, the image data is temporarily stored in the memory.

  In the image forming unit C, as an image forming unit, a drum-shaped photoconductor 21 as an image carrier, a charging means (charging step) 22 for charging the photoconductor 21 on the outer periphery thereof, and a surface potential of the charged photoconductor. Potential detecting means 220 for detecting the toner, developing means (developing process) 23, transfer conveying belt device 45 as a transferring means (transfer process), cleaning device (cleaning process) 26 for the photosensitive member 21, and light neutralizing means (light slow charge). PCL (precharge lamp) 27 as a process is arranged in the order of operation. Further, on the downstream side of the developing means 23, a reflection density detecting means 222 for measuring the reflection density of the patch image developed on the photosensitive member 21 is provided. As the photosensitive member 21, the organic photosensitive member according to the present invention is used, and the photosensitive member 21 is driven and rotated in the clockwise direction in the drawing.

  After the rotating photosensitive member 21 is uniformly charged by the charging unit 22, an image based on an image signal called from the memory of the image processing unit B by an exposure optical system as an image exposure unit (image exposure step) 30 is used. Exposure is performed. The exposure optical system as the image exposure means 30 serving as a writing means uses a laser diode (not shown) as a light source, passes through a rotating polygon mirror 31, an fθ lens 34, and a cylindrical lens 35, and the optical path is bent by a reflection mirror 32 to perform main scanning. Therefore, image exposure is performed on the photoconductor 21 at the position Ao, and an electrostatic latent image is formed by rotation (sub-scanning) of the photoconductor 21. In an example of this embodiment, the character portion is exposed to form an electrostatic latent image.

  In the image forming apparatus according to the present invention, it is preferable to use a semiconductor laser or a light emitting diode having an oscillation wavelength of 350 to 500 nm as an image exposure light source when an electrostatic latent image is formed on a photoreceptor. By using these image exposure light sources, the exposure dot diameter in the writing principal direction is narrowed down to 10 to 50 μm, and digital exposure is performed on the photosensitive member, whereby 600 dpi (dpi: the number of dots per 2.54 cm) or more and 2500 dpi. High-resolution electrophotographic images can be obtained.

The exposure dot diameter refers to the length of the exposure beam along the main scanning direction (Ld: measured at the maximum length) in a region where the intensity of the exposure beam is 1 / e ² or more of the peak intensity.

The light beams used have a solid scanner such as the scanning optical system and LED using a semiconductor laser, there is a Gaussian distribution and Lorentz distribution, etc. also the light intensity distribution is in each 1 / e ² or more regions of peak intensity The exposure dot diameter according to the present invention is used.

  The electrostatic latent image on the photoconductor 21 is reversely developed by the developing unit 23, and a visible toner image is formed on the surface of the photoconductor 21. In the image forming method according to the present invention, it is preferable to use a polymerized toner as a developer used in the developing unit. By using a polymerized toner having a uniform shape and particle size distribution in combination with the organic photoreceptor according to the present invention, an electrophotographic image with better sharpness can be obtained.

  In the transfer paper transport unit D, paper feed units 41 (A), 41 (B), and 41 (C) are provided below the image forming unit as transfer paper storage means in which transfer materials P of different sizes are stored. Further, a manual paper feeding unit 42 for manually feeding paper is provided on the side, and the transfer material P selected from any of these is fed along the transport path 40 by the guide roller 43 and fed. The transfer material P is temporarily stopped by a pair of paper feed registration rollers 44 that correct the inclination and bias of the transfer material P, and then re-feeded. The transport path 40, the pre-transfer roller 43a, and the paper feed path 46 are transferred. The toner image on the photosensitive member 21 is guided to the transfer guide belt 47 and is transferred to the transfer material P while being transferred to the transfer transfer belt 454 of the transfer transfer belt device 45 by the transfer pole 24 and the separation pole 25 at the transfer position Bo. Roll Is, the transfer material P is separated from the photosensitive member 21 surface, it is conveyed to the fixing unit 50 by the transfer conveyor belt device 45.

  The fixing unit 50 includes a fixing roller 51 and a pressure roller 52. By passing the transfer material P between the fixing roller 51 and the pressure roller 52, the toner is fixed by heating and pressing. After the toner image is fixed, the transfer material P is discharged onto the paper discharge tray 64.

  The above describes the state in which image formation is performed on one side of the transfer paper. However, in the case of double-sided copying, the paper discharge switching member 170 is switched, the transfer paper guide portion 177 is opened, and the transfer material P is indicated by the broken arrow. Conveyed in the direction.

  Further, the transfer material P is transported downward by the transport mechanism 178 and is switched back by the transfer paper reversing unit 179, and the rear end portion of the transfer material P is transported into the duplex copying paper supply unit 130 as the leading end. The

  The transfer material P moves a conveyance guide 131 provided in the duplex copying paper supply unit 130 in the paper supply direction, refeeds the transfer material P by the paper supply roller 132, and guides the transfer material P to the conveyance path 40. .

  Again, as described above, the transfer material P is conveyed in the direction of the photosensitive member 21, the toner image is transferred to the back surface of the transfer material P, fixed by the fixing unit 50, and then discharged onto the discharge tray 64.

  As an image forming apparatus according to the present invention, the above-described photosensitive member and components such as a developing unit and a cleaning unit are integrally coupled as a process cartridge, and this unit is configured to be detachable from the apparatus main body. May be. In addition, a process cartridge is formed by integrally supporting at least one of a charger, an image exposure device, a developing device, a transfer or separation device, and a cleaning device together with a photosensitive member, and a single unit that is detachable from the apparatus main body. It is good also as a structure which can be attached or detached using guide means, such as a rail of an apparatus main body.

  FIG. 2 is a cross-sectional configuration diagram showing an example of a color image forming apparatus in which the photoconductor according to the present invention can be used.

  This color image forming apparatus is called a tandem type color image forming apparatus, and includes four sets of image forming units (image forming units) 10Y, 10M, 10C, and 10Bk, an endless belt-shaped intermediate transfer body unit 7, and a feeding unit. It comprises a paper conveying means 21 and a fixing means 24. A document image reading device SC is disposed above the main body A of the image forming apparatus.

  The image forming unit 10Y that forms a yellow image includes a charging unit (charging step) 2Y, an exposure unit (exposure step) 3Y, and a developing unit disposed around a drum-shaped photoconductor 1Y as a first image carrier. A unit (developing step) 4Y, a primary transfer roller 5Y as a primary transfer unit (primary transfer step), and a cleaning unit 6Y. An image forming unit 10M that forms a magenta image includes a drum-shaped photosensitive member 1M as a first image carrier, a charging unit 2M, an exposure unit 3M, a developing unit 4M, a primary transfer roller 5M as a primary transfer unit, It has a cleaning means 6M. An image forming unit 10C for forming a cyan image includes a drum-shaped photoreceptor 1C as a first image carrier, a charging unit 2C, an exposure unit 3C, a developing unit 4C, and a primary transfer roller 5C as a primary transfer unit. It has cleaning means 6C. The image forming unit 10Bk that forms a black image includes a drum-shaped photoreceptor 1Bk as a first image carrier, a charging unit 2Bk, an exposure unit 3Bk, a developing unit 4Bk, a primary transfer roller 5Bk as a primary transfer unit, and a cleaning unit. 6Bk.

  The four sets of image forming units 10Y, 10M, 10C, and 10Bk include charging means 2Y, 2M, 2C, and 2Bk that rotate around the photosensitive drums 1Y, 1M, 1C, and 1Bk, and image exposure means 3Y, 3M, 3C and 3Bk, rotating developing means 4Y, 4M, 4C and 4Bk, and cleaning means 5Y, 5M, 5C and 5Bk for cleaning the photosensitive drums 1Y, 1M, 1C and 1Bk.

  The image forming units 10Y, 10M, 10C, and 10Bk have the same configuration except that the colors of toner images formed on the photoreceptors 1Y, 1M, 1C, and 1Bk are different, and the image forming unit 10Y is taken as an example in detail. explain.

  The image forming unit 10Y has a charging unit 2Y (hereinafter simply referred to as a charging unit 2Y or a charger 2Y), an exposure unit 3Y, a developing unit 4Y, and a cleaning unit 5Y (around a photosensitive drum 1Y as an image forming body). Hereinafter, the cleaning means 5Y or the cleaning blade 5Y) is simply disposed, and a yellow (Y) toner image is formed on the photosensitive drum 1Y. In the present embodiment, in the image forming unit 10Y, at least the photosensitive drum 1Y, the charging unit 2Y, the developing unit 4Y, and the cleaning unit 5Y are provided so as to be integrated.

  The charging unit 2Y is a unit that applies a uniform potential to the photosensitive drum 1Y. In the present embodiment, a corona discharge type charger 2Y is used for the photosensitive drum 1Y.

  The image exposure means 3Y performs exposure based on the image signal (yellow) on the photosensitive drum 1Y given a uniform potential by the charger 2Y, and forms an electrostatic latent image corresponding to the yellow image. As the exposure means 3Y, the exposure means 3Y includes an LED in which light emitting elements are arrayed in the axial direction of the photosensitive drum 1Y and an imaging element (trade name; Selfoc lens), or A laser optical system or the like is used.

  As an image forming apparatus according to the present invention, the above-described photosensitive member and components such as a developing device and a cleaning device are integrally combined as a process cartridge (image forming unit), and this image forming unit is installed in the apparatus main body. On the other hand, it may be configured to be detachable. In addition, at least one of a charging device, an image exposure device, a developing device, a transfer or separation device, and a cleaning device is integrally supported together with a photosensitive member to form a process cartridge (image forming unit), which is detachable from the apparatus main body. A single image forming unit may be detachable using guide means such as a rail of the apparatus main body.

  The endless belt-like intermediate transfer body unit 7 includes an endless belt-like intermediate transfer body 70 as a second image carrier having a semiconductive endless belt shape that is wound around a plurality of rollers and is rotatably supported.

  Each color image formed by the image forming units 10Y, 10M, 10C, and 10Bk is sequentially transferred onto a rotating endless belt-shaped intermediate transfer body 70 by primary transfer rollers 5Y, 5M, 5C, and 5Bk as primary transfer means. Thus, a synthesized color image is formed. A transfer material P as a transfer material (a support for carrying a fixed final image: for example, plain paper, a transparent sheet, etc.) housed in the paper feed cassette 20 is fed by a paper feed means 21 and a plurality of intermediates. After passing through rollers 22A, 22B, 22C, 22D and registration roller 23, they are conveyed to a secondary transfer roller 5b as a secondary transfer means, and are secondarily transferred onto a transfer material P to transfer a color image all at once. The transfer material P onto which the color image has been transferred is subjected to fixing processing by the fixing unit 24, is sandwiched between paper discharge rollers 25, and is placed on a paper discharge tray 26 outside the apparatus. Here, a transfer support for a toner image formed on a photosensitive member such as an intermediate transfer member or a transfer material is collectively referred to as a transfer medium.

  On the other hand, after the color image is transferred to the transfer material P by the secondary transfer roller 5b as the secondary transfer means, the residual toner is removed by the cleaning means 6b from the endless belt-shaped intermediate transfer body 70 in which the transfer material P is separated by curvature. The

  During the image forming process, the primary transfer roller 5Bk is always in contact with the photoreceptor 1Bk. The other primary transfer rollers 5Y, 5M, and 5C are in contact with the corresponding photoreceptors 1Y, 1M, and 1C, respectively, only during color image formation.

  The secondary transfer roller 5b contacts the endless belt-shaped intermediate transfer body 70 only when the transfer material P passes through the secondary transfer roller 5b.

  Further, the housing 8 can be pulled out from the apparatus main body A through the support rails 82L and 82R.

  The housing 8 includes image forming units 10Y, 10M, 10C, and 10Bk and an endless belt-shaped intermediate transfer body unit 7.

  The image forming units 10Y, 10M, 10C, and 10Bk are arranged in tandem in the vertical direction. An endless belt-shaped intermediate transfer body unit 7 is disposed on the left side of the photoreceptors 1Y, 1M, 1C, and 1Bk in the drawing. The endless belt-shaped intermediate transfer body unit 7 includes an endless belt-shaped intermediate transfer body 70 that can be rotated by winding rollers 71, 72, 73, 74, primary transfer rollers 5Y, 5M, 5C, 5Bk, and cleaning means 6b. Consists of.

  The present invention will be specifically described below with reference to examples, but the embodiments of the present invention are not limited to these examples.

<Preparation of amino compound>
The following amino compounds were prepared and prepared by the above synthesis method.

(Synthesis Example 1): Compound CTM-1
(Synthesis Example 2): Compound CTM-2
(Synthesis Example 3): Compound CTM-3
(Synthesis Example 4): Compound CTM-6
(Synthesis Example 5): Synthesis of Comparative Compound CTM-25 CTM-1 synthesis except that 6 parts by mass of 4- (4-biphenylyl) cyclohexanone used in Synthesis Example 1 was changed to 5.37 parts by mass of cyclohexanone Comparative compound CTM-25 was synthesized in the same manner as in the examples. The yield was 6.9 parts by mass.

(Synthesis Example 6): Synthesis of Comparative Compound CTM-26 CTM except that 6 parts by mass of 4- (4-biphenylyl) cyclohexoneone used in Synthesis Example 1 was changed to 5.44 parts by mass of isopentyl methyl ketone. -1 Comparative compound CTM-26 was synthesized in the same manner as in Synthesis Example. The yield was 4.3 parts by mass.

<< Production of photoconductor >>
A photoreceptor was prepared as follows.

<Preparation of Photoreceptor 1>
(Preparation of conductive support)
A washed cylindrical aluminum substrate was prepared as a conductive support.

(Formation of intermediate layer)
The following intermediate layer coating solution was applied to the surface of the cylindrical aluminum substrate by a dip coating method to form “intermediate layer 1” having a dry film thickness of 0.3 μm.

Intermediate layer coating solution Polyamide resin (Amilan CM-8000: manufactured by Toray Industries, Inc.) 60 parts by mass Methanol 1600 parts by mass (formation of charge generation layer)
The following charge generation layer materials were mixed and dispersed for 10 hours using a sand mill to prepare a charge generation layer coating solution. This charge generation layer coating solution was applied onto the intermediate layer by a dip coating method to form “charge generation layer 1” having a thickness of 0.2 μm.

Charge generation layer (CGL) coating solution Polycyclic quinone compound (CGM-3a) 60 parts by mass Silicone resin solution (KR5240, 15% xylene-butanol solution: manufactured by Shin-Etsu Chemical Co., Ltd.) 700 parts by mass 2-butanone 2000 parts by mass (charge transport) Layer formation)
The following charge transport layer materials were mixed and dissolved to prepare a charge transport layer coating solution. This coating solution is applied onto the “charge generation layer 1” by a dip coating method and dried by heating at 100 ° C. for 60 minutes to form a “charge transport layer 1” having a thickness of 20 μm. Was made.

Charge transport layer (CTL) coating solution Charge transport material (compound CTM-1) 200 parts by mass Bisphenol Z-type polycarbonate (Iupilon Z300: manufactured by Mitsubishi Gas Chemical Company)
300 parts by mass Tetrahydrofuran 1600 parts by mass Toluene 400 parts by mass Antioxidant (dibutylhydroxytoluene) 7.5 parts by mass (production of photoreceptors 2 to 6)
“Photoconductors 2 to 6” were prepared in the same manner as in Example 1 except that the charge transport material (Compound CTM-1) used in the preparation of the photoconductor 1 was changed to the charge transport material shown in Table 1 below. .

(Preparation of photoconductor 7)
Except for changing the polycyclic quinone compound, which is a charge blocking substance used in the preparation of the photoreceptor 1, to Y-type titanyl phthalocyanine (maximum peak angle of X-ray diffraction by Cu-Kα characteristic X-ray is 27.3 ° at 2θ). Made “Photoreceptor 7” in the same manner.

(Preparation of photoconductor 8)
“Photoreceptor 8” was produced in the same manner as Photoreceptor 1, except that the composition of the charge transport layer (CTL) coating solution used in the production of Photoreceptor 1 was as follows. When the charge transport layer material did not dissolve, it was dissolved by heating and coating was performed in that state.

Charge transport layer (CTL) coating solution Charge transport material (Comparative compound CTM-25) 200 parts by mass Bisphenol Z-type polycarbonate (Iupilon Z300: manufactured by Mitsubishi Gas Chemical Company)
300 parts by mass Tetrahydrofuran 1600 parts by mass Toluene 400 parts by mass Antioxidant (dibutylhydroxytoluene) 7.5 parts by mass (Preparation of photoreceptor 9)
“Photoreceptor 9” was prepared in the same manner as in Example 1 except that the charge transport material (Comparative Compound CTM-21) used in the preparation of Photoreceptor 8 was changed to a charge transport material (Comparative Compound CTM-26). Produced.

(Preparation of photoconductor 10)
A comparative photoreceptor 10 was produced in the same manner as the photoreceptor 8 except that the composition of the charge transport layer (CTL) coating solution used in the production of the photoreceptor 8 was as follows.

Charge transport layer (CTL) coating solution Charge transport material (Comparative compound CTM-25) 150 parts by weight Bisphenol Z-type polycarbonate (Iupilon Z300: manufactured by Mitsubishi Gas Chemical Company)
300 parts by mass Tetrahydrofuran 1600 parts by mass Toluene 400 parts by mass Antioxidant (dibutylhydroxytoluene) 7.5 parts by mass Table 1 shows charge transport materials and the like of the charge transport layer used in the production of the photoreceptor.

<Evaluation>
As an evaluation apparatus, the exposure light source of the copier “bizhub PRO C6500” (manufactured by Konica Minolta Business Technologies) was changed to a violet laser with a laser oscillation wavelength of 408 nm, and the exposure dot diameter was changed from 60 μm to 20 μm. Prepared.

  The evaluation of the image was performed based on the occurrence of spot defects in the halftone image, the image fog, and the sharpness of the image. Note that, as evaluation criteria, 合格 and ○ are acceptable and × is unacceptable (problematic).

(Light resistance of photoconductor)
After exposing the photoconductor produced above with a solar simulator device under the following conditions, the absorbance of the photoconductor was measured. Thereafter, the photosensitive member was loaded into the image forming apparatus, a solid image was printed, and an image density difference was evaluated.

Exposure light source: Xenon lamp Light intensity: Approximately 100,000 lx
Exposure time: 30 minutes Exposure area: 2cm x 2cm
Evaluation criteria: Absorbance difference of photoreceptor ◎: No difference in absorbance at a wavelength of 280 to 320 nm between exposed part and unexposed part ○: Absorbance difference at a wavelength of 280 to 320 nm between exposed part and unexposed part is 0.50 or less × : The difference in absorbance at a wavelength of 280 to 320 nm between the exposed part and the unexposed part exceeds 0.50.

Evaluation criteria: Difference in image density ◎: No difference in density in the printed image between the exposed part and the unexposed part ○: A difference in density between the exposed part and the unexposed part in the printed image is 0.10 or less. There is a practical problem because the density difference between the exposed and unexposed areas of the printed image exceeds 0.10.

(Pochi defect)
The evaluation of the point defect was performed as follows.

“Photosensitive members 1 to 13” are sequentially set at the black position in the image forming apparatus, and a halftone image having an image density of 0.4 is printed on A4 fine paper (64 g / m) in a low temperature and low humidity (10 ° C., 15% RH) environment. ² ) was printed. Then, after printing 100,000 text images with a print area of 7%, a halftone image with an image density of 0.4 was printed on A4 fine paper (64 g / m ² ) in a low-temperature, low-humidity (10 ° C., 15% RH) environment. A print was made. The evaluation was performed by the number of spot defects (diameter of 0.4 mm or more) per one period of the photoreceptor on the halftone image having an image density of 0.4 printed at the initial stage and after 100,000 sheets.

Evaluation Criteria A: Poor defect occurrence frequency is good at an average of 3 or less per one period of photoconductor ○: Pochi defect occurrence frequency is 4-8 per one period of photoconductor, no problem in practical use ×: Pochi There are practical problems with the occurrence frequency of defects of 9 or more per one period of the photoconductor.

(Image cover)
The image fog was evaluated by the difference between the fog density of the plain image after the initial printing and the printing of 100,000 sheets, and the blank paper density of the fine paper (64 g / m ² ).

  Specifically, the white paper density of the fine paper was measured at 20 locations on the A4 plate, the average value was measured as the white paper density, and the fog density of the plain image after the printing of 100,000 sheets was measured at 20 locations on the A4 plate, The average value is defined as the fog density. The density was measured using a reflection densitometer “RD-918 (manufactured by Macbeth)”.

Evaluation criteria A: Image fog is less than 0.003, good ○: Image fog is 0.003 or more and less than 0.010, practically no problem ×: Image fog density is 0.010 or more, practical problem Level that becomes.

(Image sharpness)
As for the sharpness of the image, the original image (3, 5 point character image) is printed under the high temperature and humidity environment (30 ° C, 80% RH) after the completion of printing at the initial stage and 100,000 sheets. Evaluated by crushing characters in the image.

Evaluation criteria ◎: 3 points and 5 points are clear and easily readable ○: 3 points are partially illegible, 5 points are clear and easily readable ×: 3 points are almost unreadable 5 points Is partly or entirely unreadable.

  Table 2 shows the evaluation results.

As is apparent from Table 2, the “photoconductors 1 to 5 and 7” of Examples 1 to 5 and 7 using the amine compound of the present invention as a charge transport material and the photoconductor 6 of Reference Example 6 are the initial images. In addition, good evaluation results were obtained for both the 100,000-printed images, indicating that the object of the present invention was satisfied. On the other hand, “Photoconductors 8 to 10” of Comparative Examples 1 to 3 using an amine compound other than the amine compound of the present invention as a charge transport material failed in any of the evaluation items, and satisfied the object of the present invention. It turns out that there is no.

1 is a cross-sectional configuration diagram illustrating an example of an image forming apparatus in which a photoconductor according to the present invention can be used. 1 is a cross-sectional configuration diagram illustrating an example of a color image forming apparatus in which a photoconductor according to the present invention can be used.

Explanation of symbols

10Y, 10M, 10C, 10Bk Image forming unit 1Y, 1M, 1C, 1Bk Photoconductor 2Y, 2M, 2C, 2Bk Charging unit 3Y, 3M, 3C, 3Bk Exposure unit 4Y, 4M, 4C, 4Bk Developing unit

Claims (4)

An amine compound characterized by being one of the following compounds CTM-1, CTM-2, CTM-3, CTM-6 and CTM-13 .

An electrophotographic photoreceptor comprising a photosensitive layer containing a charge generation material and a charge transport material on a conductive support, wherein the charge transport material is an amine compound represented by the following general formula (1): An electrophotographic photoreceptor .

(In the general formula (1), Ar ¹ , Ar ² , Ar ⁴ and Ar ⁵ each independently represent a phenyl group which may have one or two methyl groups, and Ar ³ and Ar ⁶ each represent (Independently represents a phenylene group which may have one methyl group. X ¹ and X ² represent a structure represented by the following general formula (2).)

(In general formula (2), R _{1 to} R ₈ are each independently hydrogen or a methyl group, and R ₉ represents a biphenyl group or a biphenyloxy group.) 3. The electrophotographic photosensitive member according to claim 2, wherein the charge generating material contained in the photosensitive layer is a polycyclic quinone compound . An image having exposure means for forming an electrostatic latent image on a photosensitive member using a semiconductor laser having an oscillation wavelength of 350 to 500 nm or a writing light source of a light emitting diode, and developing means for developing the electrostatic latent image into a toner image 4. An image forming apparatus according to claim 2, wherein the photoconductor is the electrophotographic photoconductor according to claim 2 .

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